For women diagnosed with a form of breast cancer known as estrogen receptor positive (ER+) breast cancer, tamoxifen is an essential drug used in the treatment and prevention of recurring breast cancer.
Currently, tamoxifen is used in a one-size-fits-all approach where the same dose is prescribed for every patient. New research at Lawson Health Research Institute has found that in addition to patient-specific genetic factors, lack of exposure to vitamin D during the long winter months affects the body's ability to metabolize the drug.
The findings, which have been reported in the journal Breast Cancer Research and Treatment, are the first to identify this seasonal effect. Dr. Richard Kim, who is a physician at London Health Sciences Centre (LHSC) and holds the Wolfe Medical Research Chair in Pharmacogenomics at Western University, reports that during the winter months nearly 30 percent of patients are at risk for less than optimal level of the active form of tamoxifen, called endoxifen, and therefore may not benefit as much from the therapy.
In the liver, tamoxifen is converted to the active form of the drug called endoxifen by a protein called CYP2D6. "We know that endoxifen is nearly 100 times more potent against the estrogen receptor relative to tamoxifen," says Dr. Kim. "Our research has shown that patients with normal CYP2D6 activity can easily convert tamoxifen to endoxifen, whereas patients with no CYP2D6 activity have a significantly limited ability to convert tamoxifen to endoxifen."
In addition to the seasonal effect, Dr. Kim found that the simultaneous use of a common antidepressant can also substantially lower the body's ability to metabolize endoxifen levels. "Patients who are either partly or completely deficient in CYP2D6 and who are prescribed the SSRI class of antidepressants are at major risk for subtherapeutic endoxifen levels," says Dr. Kim.
With nearly 10 percent of the population completely lacking CYP2D6 enzymatic activity, these findings have important clinical applications. "Our most recent findings are important additions to the pool of data we already have on tamoxifen therapy," says Dr. Kim. "These new clinical and genetic markers can aid physicians to better identify patients who will benefit from tamoxifen, as well as those patients at risk for suboptimal benefit."
Lawson Health Research Institute. As the research institute of London Health Sciences Centre and St. Joseph's Health Care London, and working in partnership with Western University, Lawson Health Research Institute is committed to furthering scientific knowledge to advance health care around the world. http://www.lawsonresearch.comFor more information, please contact:
Robert DeLaet | EurekAlert!
Scientists learn more about how gene linked to autism affects brain
19.06.2018 | Cincinnati Children's Hospital Medical Center
Overdosing on Calcium
19.06.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
Light detection and control lies at the heart of many modern device applications, such as smartphone cameras. Using graphene as a light-sensitive material for...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
19.06.2018 | Physics and Astronomy
19.06.2018 | Life Sciences
19.06.2018 | Physics and Astronomy